In the first three months of 2002, just 9% of all new mortgages were taken as interest only - but by the last quarter of 2005, the figure had risen to 23%. And amongst first time buyers, the figures rose from 6% to 15%. (Source: Council of Mortgage Lenders.)

The reason is obvious. It's down to family economics. With an interest only mortgage, the monthly repayments only repay the ongoing interest so your monthly repayment is low. Repayment of the capital borrowed is delayed to the end of the mortgage when it has to be repaid as a lump sum. So the popularity of interest only mortgages is a reflection of borrowers wanting to minimise their fixed monthly outgoings in order to preserve their lifestyle they still want their nice cars, nights out and holidays abroad. But their reluctance to cut back on their life style spending, combined with steadily rising house prices, could be storing up problems for the future. If they're not repaying some of the capital now, how are they going to repay it?

Egged on by the concerns voiced by the Financial Services Authority (FSA), many lenders are now becoming much stricter when assessing an application for an interest only mortgage. They're insisting that there's a viable repayment vehicle in place before they'll payout the money. These repayment vehicles could be the tax-free cash forecast from a pension policy, or an ISA or some other regular investment or savings scheme. The danger is that having got the mortgage, the borrower subsequently cancels their savings scheme.

If that were to happen, when retirement finally arrives accompanied by the looming commitment to repay the mortgage capital, they'll be faced with having to sell their home and down size simply to free up money to repay the mortgage. And that's a scenario that lenders and the FSA are anxious to avoid.

Twenty years ago interest only mortgages were the accepted norm with endowment policies being used as the most popular investment to repay the capital. But as we now know, returns on endowment policies have not been as high as many had assumed. This has left thousands of homeowners with a capital repayment shortfall. Endowment policies have certainly failed to be the guaranteed repayment solution that many of us had assumed twenty years ago. So, in today's economic and investment environment, how certain can you be of any scheme to repay the capital?

When the shortcomings of endowment policies slowly became understood, interest only mortgages fell out of favour and repayment mortgages took over as the norm. But once again the pendulum is swinging. Interest only mortgages are back in a big way. It's the result of high house prices and people straining to get onto and up the housing ladder without wanting to economise on other areas of their spending.

We're sure that the pressures within family finances will continue to fuel the demand for interest only mortgages. However, it becomes the duty of mortgage brokers and the lenders to point out the alternatives open to their clients.

In the past, a 25 year mortgage term has been the norm for a young buyer. But now they can stretch the repayment period to 30, even 35 years. This makes the payments on a repayment mortgage far more affordable.

For example, the monthly repayments for a 125,000 repayment mortgage over 25 years at say, 4.9% cost 731.69 per month, but if the repayment period was stretched to 35 years, the repayment drops to 628.16 per month, a cash flow saving of 103.53.

The idea is that as and when family finances permit, borrowers can reduce the capital outstanding by making optional lump sum repayments. In practice, people tend to move house every eight to ten years and at each move a new mortgage has to be organised. These moves then represent an obvious opportunity to reassess long-term family finances.

But other solutions are available. You could arrange a mortgage where part of the loan is on a repayment basis with the balance on interest only. It's a mid way option. At least these types of mortgage start the repayment process and later when you move home or the family income builds, you can take the opportunity to reassess the most suitable type of mortgage.

But please bear in mind that you shouldn't speculate when it comes to your home finances. Mortgages are complicated and there is never just one solution. Our advice is take professional advice and use a mortgage broker who can search the entire market.